In dialysis clinics for hemodialysis, large numbers of patients are treated simultaneously. Each patient is thus connected to a dialysis machine, a so-called monitor, which prepares the dialysis solution and administers the solution to a dialyzer, which is connected to the patient.
In monitors which are presently in use, such as the GAMBRO AK-100 monitor, preparation of the dialysis solution normally takes place by mixing two dialysis concentrates to produce a desired composition and concentration.
The dialysis concentrate can be an A-concentrate, which consists of acetic acid, sodium chloride, potassium chloride, calcium chloride and magnesium chloride, and a B-concentrate, consisting of bicarbonate. Reference is made to European Patent No. B1-0 278 100 for further details thereof.
These concentrates are diluted with water, which is normally obtained from a particular water outlet at each treatment location. The water must be specially treated so that it contains as few impurities as possible, and is normally prepared by the so-called RO (reverse osmosis) process. Such a process is described, for example, in European Patent Nos. B1-0 058 303 and BI-0 058 304.
The water is usually purified at a central location, and is conducted to each patient location in a particular conduit system which is constructed with the intention of reducing the possibilities of bacterial contamination. Furthermore, the conduit system is regularly disinfected by feeding warm water, at a temperature above 90.degree. C., through the system.
German Patent No. A1-34 43 911 describes a method and an apparatus for the batchwise preparation of a dialysis solution consisting of common salt, magnesium, calcium, potassium and glucose by mixing with so-called "zero-conductivity water," i.e., purified water, in a large tank. The thus-prepared dialysis solution is then drained into containers of about 10 liters each, and placed at the dialysis clinic's disposal to form the above-mentioned A-concentrate after the addition of acid (which can take place in the monitor itself). The disadvantage with this process is that heavy concentrate-containing containers must be physically handled by the personnel and transported or carried to each patient location.
German Patent No. C2-42 03 905 describes the distribution of a centrally prepared dialysis solution by means of a conduit system. The disadvantage with such central distribution of dialysis solution is that the dialysis solution is a very good nutritional medium for many bacteria. According to German Patent No. C2-42 03 905, a sterile filter is employed, though this can become quite expensive. Furthermore, very effective disinfection of the conduit system is required. The conduits must first be rinsed clean to remove the dialysis solution, after which hot water or other disinfecting agents are circulated through the conduits.